1. Field of the Invention
The present invention relates to a hose clamp holding structure for positioning and holding a hose clamp on an outer periphery of an end portion of a hose. The hose clamp is used, for example, for connection of a fuel hose and a pipe in a motor vehicle.
2. Description of the Related Art
In a fuel piping of a motor vehicle, for example, for fluid communication between pipes, used is a rubber or elastomer fuel hose including a gasoline fuel impermeable layer. A gasoline fuel path is constructed between the pipes by fitting each end portion of the fuel hose to an outer periphery of each of the pipes.
In order to prevent leakage of gasoline fuel at a joint between the fuel hose and the pipe, a seal ring is disposed in an inner periphery of the fuel hose for providing a seal therebetween. And, in order to prevent dislodgment of the fuel hose from the pipe, the fuel hose is tightly fitted to the outer periphery of the pipe. Unlike a resin tube, however, sufficient securing strength with respect to the pipe cannot be expected for the rubber or elastomer fuel hose by itself. So, in a connecting structure typically employed, a hose clamp is fitted on an outer periphery of an end portion of the fuel hose, and the fuel hose is tightened and secured to the pipe by the hose clamp (for example, refer to Patent Document 1).
A hose clamp for firmly securing the fuel hose to the pipe comprises an annular clamp body, and an operating portion for diametrically contracting and expanding the clamp body. The operating portion is, for example, in a form of an operation screw. When this hose clamp is used, the clamp body in diametrically expanded state is preliminarily fitted on a clamp mounting portion of an end portion of the hose while being positioned in a longitudinal direction of the hose, and then, the fuel hose with the hose clamp is fitted to the pipe. After that, the clamp body is diametrically contracted, for example, by rotating the operation screw with an electric driver or air driver, to tighten the fuel hose to the pipe. In this manner, connecting work may be carried out relatively easily.
Meanwhile, for example, in the hose clamp with an operation screw, it is necessary to turn the hose clamp on the outer periphery of the end portion of the hose so as to locate the operation screw in a predetermined circumferential position when the operation screw is rotated, and to hold the hose clamp non-rotationally or non-turnably while the clamp body is diametrically contracted by rotating the operation screw. Thus, basically, connecting work requires both hands. However, in many cases, connecting work of the fuel hose and the pipe is done in a narrow engine compartment where parts are closely arranged and an operator has difficulty to do connecting work by using his/her both hands freely. So, it bothers considerably the operator to tighten the hose clamp.
A technique for eliminating such inconvenience is disclosed. For example, Patent Document 2 discloses a hose clamp holding structure where an anti-rotation engaging portion protruding in a longitudinal direction of a hose is formed on a clamp body of a hose clamp, an engaging recessed portion is formed in an outer periphery of an end portion of the hose for receiving the anti-rotation engaging portion, and thereby the hose clamp can be positioned circumferentially with respect to the hose.
[Patent Document 1] JP-A-2003-314759
[Patent Document 2] JP-A-4-194486
By the way, for ensuring anti-rotation function with respect to the anti-rotation engaging portion of the clamp body, it is effective to provide a pair of raised portions on an outer periphery of the end portion of the hose in circumferentially spaced relation to define an engaging recessed portion between the pair of the raised portions. And, the pair of the raised portions may be formed on an outer end or an outer end portion of the end portion of the hose to fit the hose clamp on a portion of the hose longitudinally inward from the pair of the raised portions. In this arrangement, the raised portions prevent the hose clamp from falling off or slipping off from the end portion of the hose. And, for preventing the hose clamp from escaping via other region of the hose than the raised portions it is favorable that, an annular positioning projection is formed on outer periphery of the outer end portion of the end portion of the hose. The annular positioning projection could be designed in low height in order to increase a space around the outer periphery of the end portion of the hose as much as possible. However, in this case, there is a concern that the hose clamp obliquely passes through the end portion of the hose, from a diametrically opposite side of the raised portions toward the raised portions, then, completely passes through the raised portions and falls off entirely of the end portion of the hose.
Under the circumstances described above, it is an object of the present invention to provide a hose clamp holding structure for holding a hose clamp consistently on an end portion of a hose.